Saturday, 21 January 2012

Bat Luck

In early October 2011, near the end of her most recent, 3-month trip to South Sudan to survey the country’s small mammals, Bucknell University mammalogist and bat specialist DeeAnn Reeder set out with a small team of wildlife officers and a graduate student just before dusk in search of a colony of bats known as flying foxes.
Reeder was barely five minutes into the expedition when she noticed that her husband, Thomas, who had been trailing behind on his motorcycle, had vanished from the rearview mirror of her Land Rover.
Earlier that day, Thomas had broken his helmet visor and was having trouble keeping the dust from the parched, clay road from irritating his eyes. Moments before Reeder noticed his absence, Thomas had removed one hand from the handle bar to rub his eyes and lost control of the motorcycle.
Reeder immediately backtracked and found her husband in agony on the side of the road. After dropping off the rest of the team at their base camp in the nearby town of Mogiri, she bribed her way across the Ugandan border and checked Thomas into a hospital around midnight.
The pair returned to Mogiri the next day—Thomas drowsy from taking codeine and sporting a flimsy arm sling to support a snapped collarbone—only to find that Reeder’s graduate student, Megan Vodzak, had fallen seriously ill with malaria and was running a high fever. While Reeder was playing nurse in the days that followed, she got word that her eldest daughter, a type 1 diabetic who had returned from South Sudan to their home in Pennsylvania a month earlier, had been admitted to a hospital after a delayed bout of malaria triggered an episode of diabetic ketoacidosis.
The sequence of disasters cut short Reeder’s trip to South Sudan by more than a week and scrapped a planned expedition to a region near the border of Congo that harbors a profusion of bat species. But despite being plagued by illness (Thomas eventually landed in a hospital with malaria four weeks after returning to the States) and just plain bad luck, over the previous two and a half months the team had still managed to collect hundreds of bat and rodent specimens as well as tissue and blood samples from about 20 bat species—all of which will help Reeder, along with her collaborators at the Centers for Disease Control and Prevention (CDC) and the Smithsonian Institution, understand how small mammal biodiversity relates to disease ecology.
Although she may be best known as coeditor of Mammal Species of the World—the standard text on mammalian taxonomy—Reeder’s particular focus for the past 15 years has been bat physiology and behavior. She helped identify the fungus Geomyces destructans as the cause of white-nose syndrome, the disease that has been decimating North American bat populations for the past several years.
Reeder first traveled to what is now South Sudan in 2004 to accompany Thomas, an Episcopalian minister, on a humanitarian mission to build an orphanage. Very quickly however, she realized the embattled region had untapped research potential. “I just kept looking up at the night sky thinking there are some amazing bats here,” she says.
At least 80 species of bats inhabit South Sudan alone—almost twice the number in the entire United States—and those are just the ones that are known. With the help of funding from the National Geographic Society, the Eppley Foundation for Research, and Bucknell University, Reeder has organized four trips to South Sudan with her family, graduate students, and field technicians, all of whom help Reeder raise nets high into darkened forest canopies to catch bats. “It’s like being a kid in a candy store,” Reeder says. “Everything you catch is something new to you, or maybe even new to science.”
During her latest journey to the country in 2011, and working with no electricity or running water and scant protection from the elements, Reeder and her team performed makeshift experiments in the field to probe the immune capabilities of the captured bats. Vodzak injected bats with lipopolysaccharides (LPS), a bacterial membrane component known to induce an immune response in mammals, and also mixed bat plasma with freshly-drained chicken blood to test whether the complement protein system in the bat’s plasma lysed the chicken red blood cells. Although Vodzak has yet to analyze those experiments, the team was surprised to see that the majority of the bats didn’t spike a fever in response to the LPS challenge. It was as if their immune systems were ignoring the LPS, Reeder explains.
“One of the things that has become apparent is that bats are doing some things differently than other mammals,” Reeder says. During her postdoc days at Boston University, Reeder was equally surprised to see that two species of flying foxes did not produce an immunoglobulin response after being injected with the tetanus toxoid.
“This may be related to the fact that bats can carry all kinds of really nasty diseases,” Reeder says. Indeed, in the past decade, an increasing body of literature has pointed toward bats as an important reservoir for deadly viruses such as Ebola and Marburg, notes virologist and Reeder’s CDC collaborator Jonathan Towner.
For her most recent trip to South Sudan, the CDC equipped Reeder with liquid-nitrogen tanks, generator-driven centrifuges, and small refrigerators to preserve the blood, livers, spleens, kidneys, hearts, and lungs of the bats her team captured. “It’s the perfect arrangement,” Towner says. Over the next months, both Reeder and Towner will test the blood and tissue for viral load and cytokine levels, among other things.
Despite all her misadventures, Reeder is eagerly planning a return to South Sudan in June 2012. She hopes not only to finally set up camp near the Congo border, but also to remain the only member of her family not to have contracted malaria.
Quote
It’s like being a kid in a candy store. Everything you catch is something new to you, or maybe even new to science.
-DeeAnn Reeder, Bucknell University